template.c

CGI程序实例

/* template.c */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "cgivars.h"
#include "htmllib.h"
#include "io_lib.h"

// should be set if CGI program is executed on a test-pc for testing purpose:
// must be commented if build is for target-hardware!
//#define TEST

// for debug output:
//#define DEBUG

// if changing device names is wished:
//#ifdef DEVICE_NAME_CHANGEABLE

#define DEVICE_NAME_LEN 40

/*
TODO:
-----

- make device names changeable 
	(set appropriate debug-constant 
	and change constant names in html-form to the given variables,
	make these variable global to template.c and io_lib.c.
	now a plausibility-check is necessary to catch invalid device names)
- enable also hex-values in input-boxes for LED-values
- plausibility-check for input values (forbid special characters etc.),
	maybe this is done very easily in javascript (execute javascript which does
	the plausibility-check and then submit the form if the values are ok)

*/

int template_page(char **postvars, char **getvars, int form_method) {
	int i;

	// lokale variablen für eingabefelder
	char mode[8]					= "\0";

#ifdef DEVICE_NAME_CHANGEABLE
	char leds_green__device[DEVICE_NAME_LEN]	= LEDS_GREEN;
	char leds_red__device[DEVICE_NAME_LEN]		= LEDS_RED;
	char seg7__device[DEVICE_NAME_LEN] 		= SEG7;
	char lcd__device[DEVICE_NAME_LEN]		= LCD;
	char switches__device[DEVICE_NAME_LEN]		= SWITCHES;
	char buttons__device[DEVICE_NAME_LEN]		= BUTTONS;
#endif
	char leds_green__value[STRING_LEN]	= "0";
	char leds_red__value[STRING_LEN]	= "0";
	char seg7__value[STRING_LEN]		= "0";
	char lcd__value[32]			= "0";
	char switches__value[STRING_LEN]	= "0";
	char buttons__value[STRING_LEN]		= "0";

#ifdef DEBUG // lists all variables which are coming from GET request
	for (i=0; getvars[i]; i+= 2)
		printf("<li>DEBUG: [%s] = [%s]\n", getvars[i], getvars[i+1]);
#endif

	// if we got a POST request: copy all contents to local variables
	if(form_method == POST) {
#ifdef TEST		
		printf("TEST is set, so no I/O interaction is possible");
#endif
		for (i=0; postvars[i]; i+= 2) {
			if(!strcmp(postvars[i],"leds_green__value"))
				strcpy(leds_green__value,postvars[i+1]);
			if(!strcmp(postvars[i],"leds_red__value"))
				strcpy(leds_red__value,postvars[i+1]);
			if(!strcmp(postvars[i],"seg7__value"))
				strcpy(seg7__value,postvars[i+1]);
			if(!strcmp(postvars[i],"lcd__value"))
				strcpy(lcd__value,postvars[i+1]);
			if(!strcmp(postvars[i],"mode"))
				strcpy(mode,postvars[i+1]);
			// if changing device names if wished:
#ifdef DEVICE_NAME_CHANGEABLE
			if(!strcmp(postvars[i],"leds_green__device"))
				strcpy(leds_green__device,postvars[i+1]);
			if(!strcmp(postvars[i],"leds_red__device"))
				strcpy(leds_red__device,postvars[i]);
			if(!strcmp(postvars[i],"seg7__device"))
				strcpy(seg7__device,postvars[i]);
			if(!strcmp(postvars[i],"lcd__device"))
				strcpy(lcd__device,postvars[i]);
			if(!strcmp(postvars[i],"buttons__device"))
				strcpy(buttons__device,postvars[i]);
			if(!strcmp(postvars[i],"switches__device"))
				strcpy(switches__device,postvars[i]);
#endif

#ifdef DEBUG	// lists all variables which are coming from POST request
			printf("<li>DEBUG: [%s] = [%s]\n", postvars[i], postvars[i+1]);
#endif
		}

#ifndef TEST
		// write values to hardware
		if(!strcmp(mode,"write")) {		
			write_dev(leds_red, leds_red__value);
			write_dev(leds_green, leds_green__value);
			write_dev(seg7, seg7__value);
			if(i = write_lcd(lcd__value))
				printf("ERROR: write_lcd error code %i\n",i); 
		}
		
		// read values from hardware even in write mode
		if(!strcmp(mode,"read") || !strcmp(mode,"write")) {
			//ltoa(buttons__value,read_dev(buttons));
			//ltoa(switches__value,read_dev(switches));
			sprintf(buttons__value, "%d", read_dev(buttons));
			sprintf(switches__value, "%ld", read_dev(switches));
		}
#endif
	}

	// layout table for device inputs
  	printf("<fieldset>\n");
	printf("<legend>Write</legend>\n");
	printf("<FORM ACTION=\"%s\" METHOD=POST>\n", "/cgi-bin/cgi_demo");	
	printf("<table border=\"0\" width=\"1024\">\n");
	printf("<tr>\n");
	printf("	<td width=\"200\"></td>\n");
	printf("	<td width=\"350\"><strong>Configuration of device files</strong></td>\n");
	printf("	<td><strong>Writeable values</strong></td>\n");
	printf("</tr>\n");
	printf("</table>\n");
	printf("<table border=\"0\" width=\"1024\">\n");
	printf("<tr>\n");
	printf("	<td width=\"200\">Green LEDs:</td>\n");		
	printf("	<td width=\"350\"><input name=\"leds_green__device\" type=\"text\" size=\"30\" maxlength=\"50\" value=\"%s\" readonly disabled></td>\n", LEDS_GREEN);
	printf("	<td><input name=\"leds_green__value\" type=\"text\" size=\"20\" maxlength=\"20\" value=\"%s\"> (max. 511)</td>\n", leds_green__value);
	printf("</tr>\n");
	printf("<tr>\n");
	printf("	<td>Red LEDs:</td>\n");
	printf("	<td><input name=\"leds_red__device\" type=\"text\" size=\"30\"  maxlength=\"50\" value=\"%s\" readonly disabled></td>\n", LEDS_RED);
	printf("	<td><input name=\"leds_red__value\" type=\"text\" size=\"20\" maxlength=\"20\" value=\"%s\"> (max. 262143)</td>\n", leds_red__value);
	printf("</tr>\n");
	printf("<tr>\n");
	printf("	<td>7-segment Display:</td>\n");
	printf("	<td><input name=\"seg7__device\" type=\"text\" size=\"30\"  maxlength=\"50\" value=\"%s\" readonly disabled></td>\n", SEG7);
	printf("	<td><input name=\"seg7__value\" type=\"text\" size=\"8\" maxlength=\"8\" value=\"%s\"> (max. 8 characters, hex values)</td>\n", seg7__value);
	printf("</tr>\n");
	printf("<tr>\n");
	printf("	<td>LC-Display:</td>\n");
	printf("	<td><input name=\"lcd__device\" type=\"text\" size=\"30\"  maxlength=\"50\" value=\"%s\" readonly disabled></td>\n", LCD);
	printf("	<td><input name=\"lcd__value\" type=\"text\" size=\"32\" maxlength=\"32\" value=\"%s\"> (max. 32 characters)</td>\n", lcd__value);
	printf("</tr>\n");
	printf("</table>\n");
	printf("<input type=\"hidden\" name=\"mode\" value=0>\n");
	printf("<INPUT TYPE=\"submit\" VALUE=\"Submit\" onclick=\"this.form.mode.value='write'\"><INPUT TYPE=reset VALUE=\"Reset\">\n");
  	printf("</fieldset>\n");

	// layout table for outputs
	printf("<fieldset>\n");
	printf("<legend>Read</legend>\n");
	printf("<table border=\"0\" width=\"1024\">\n");
	printf("<tr>\n");
	printf("	<td width=\"200\"></td>\n");
	printf("	<td width=\"350\"><strong>Configuration of device files</strong></td>\n");
	printf("	<td><strong>Readable values</strong></td>\n");
	printf("</tr>\n");
	printf("</table>\n");

	printf("<table border=\"0\" width=\"1024\">\n");
	printf("<tr>\n");
	printf("	<td width=\"200\">Switches:</td>\n");
	printf("	<td width=\"350\"><input name=\"switches__device\" type=\"text\" size=\"30\" maxlength=\"50\" value=\"%s\" readonly disabled></td>\n", SWITCHES);
	printf("	<td><input name=\"switches__value\" type=\"text\" size=\"10\" maxlength=\"10\" value=\"%s\" readonly disabled></td>\n", switches__value);
	printf("</tr>\n");
	printf("<tr>\n");
	printf("	<td>Buttons:</td>\n");
	printf("	<td><input name=\"buttons__device\" type=\"text\" size=\"30\"  maxlength=\"50\" value=\"%s\" readonly disabled></td>\n", BUTTONS);
	printf("	<td><input name=\"buttons__value\" type=\"text\" size=\"10\" maxlength=\"10\" value=\"%s\" readonly disabled></td>\n", buttons__value);
	printf("</tr>\n");
	printf("</table>\n");
	printf("<INPUT TYPE=submit VALUE=\"Refresh\" onclick=\"this.form.mode.value='read'\">\n");
	printf("</FORM>\n");
  	printf("</fieldset>\n");
			
	return 0;	
}